Mark

4 comments by Mark

  • Nice chemistry but there might be a problem.

    The problem is that the sulfur end product has the potential to be a rather nasty compound. The worst smelling sulfur compound which I have heard of with the strongest smell has to be either tert-butyl thiol or Me3SiSSiMe3. If the process forms Et3SiSSiEt3 then it might well convert the slightly offensive things like benzothiophene and dibenzothiophenes into something which has a lot of potential to be more mobile and offensive.

    The normal end product of HDS is to form hydrogen sulfide which can be scrubbed out of gas streams with zinc oxide or removed in some other methods such as combustion with a limited amount of oxygen to form SO2 which then reacts with H2S to form sulfur and water.

    I have never tried to work with Et3SiSSiEt3, but might have similar properties to the methyl compound and thus be quite horrible. An alternative to HDS (hydrodesulfurisation) is to use oxidation of the sulfur compounds to change their properties followed by some separation such as solvent extraction.

    Commented on:20 March 2017 16:53

    Car exhaust fumes

    Squeezing the last of the sulfur from fuels

  • Regarding electric cars, I quite agree with Norman Groocock that in general the more energy conversions which occur then the lower the well to wheel efficency. From a climate change point of view it makes more sense to put DERV in a car or taxi rather than to burn the fuel oil to generate electric power which is then used to charge a secondary cell.

    I hold the view that a "zero emissions vehicle" is in fact an "emissions elsewhere vehicle". But I heard an interesting argument some years ago from an academic at a climate change lecture. This academic agreed that a diesel car would be better from a CO2 release point of view than an electric car running on fossil fuel produced electric power.

    But the academic argued that if we moved over to electric vehicles which are charged from the electricity grid then if the electric power production was done using systems which do not release carbon dioxide or other greenhouse gases into the air then it would be much better from a climatic change point of view.

    I think we need to look at the whole of the lifecycle of the equipment used for electric power production and energy conversion. For example lanthanides are needed for the magnets and other parts of some of these potentially greener systems. The problem is that lanthanide mining creates pollution, however lanthanide recycling should produce far less pollution. Thus it makes sense to do research on the recycling of materials such as the lanthanides. A similar argument can be made for some other materials needed in high tech or green equipment.

    Commented on:19 March 2017 18:56

    0317CW - Letters

    Letters: March 2017

  • I am working in Sweden, I do admit that I pay a lot of tax but as a tax payer I think I get a better deal than I did when I was a tax payer in the UK.

    Commented on:28 November 2016 18:24

    Sweden - Archipelago

    Sweden

  • Thank goodness for that, homopathic medicine in my view is a waste of money.